This invention generally relates to perfusion type intravascular catheters, particularly catheters for use in percutaneous transluminal coronary angioplasty (PCTA).
In a typical PTCA procedure a dilatation balloon catheter is advanced over a guidewire to a desired location within the patient's coronary anatomy where the balloon of the dilatation catheter is properly positioned within the stenosis to be dilated. The balloon is then inflated to a predetermined size with radiopaque liquid at relatively high pressures generally 4-20 atmospheres) to dilate the stenosed region of the diseased artery. One or more inflations may be needed to effectively dilate the stenosis. The catheter may then be withdrawn from the stenosis or advanced further into the patient's coronary anatomy to dilate additional stenoses.
A high number of angioplasty procedures result in a dissected arterial lining which can collapse causing an acute closure of the arterial passageway. When an acute closure of the arterial passageway occurs, a perfusion device is usually advanced over the in-place guidewire to ensure adequate blood flow distal to the dissected lining until the lining be resecured to the artery wall or a by-pass procedure commenced. Preferably, a dilatation balloon catheter with perfusion capabilities is advanced over the in-place guidewire until the balloon crosses the dissection and then the balloon is inflated to press the dissected lining into place against the arterial wall. With the balloon inflated, blood is forced to pass through a perfusion passageway through the balloon to discharge the blood distal to the dissected arterial region. In this manner, the balloon remains in an inflated condition for sufficiently long periods of time, e.g. from about 0.5 to about 6 hours, for the natural healing process to resecure the dissected lining to the arterial wall.
Balloon dilatation catheters with perfusion capabilities have been available from Advanced Cardiovascular Systems, Inc. for a number of years, including the RX Perfusion and Lifestream Coronary Dilatation Catheters, which have met with much commercial success. Such catheters are described in U.S. Pat. No. 5,496,275 (Sirhan et al) an U.S. application Ser. No. 08/183,574, filed on Jan. 18, 1994 which are incorporated herein by reference in their entirety. The perfusion catheters presently on the market are predominantly rapid exchange type dilatation catheters due to the frequent need to advance a perfusion catheter over an in-place guidewire when an acute occlusion occurs after the original dilatation catheter has been deflated and withdrawn from the stenotic region.
Rapid exchange dilatation catheters with perfusion capabilities are more frequently being used as primary devices because if an arterial dissection does occur a perfusion catheter is already in place and all that is needed is to position the balloon within the dissected region and reinflate the balloon to cause the perfusion of oxygenated blood through the catheter and distal thereto and to hold the dissected lining against the arterial wall. However, with the advent of high pressure balloon use with rapid exchange type catheters, there is a tendency for the tubular member extending within the balloon to collapse, blocking the guidewire passageway. If the catheter is a perfusion type catheter, such a collapse blocks or at least restricts the passage of blood therethrough.